, ZOL1603 ASSIGNMENT 5 SEMESTER 2 2026
DUE DATE:15 SEPTEMBER
QUESTION 1
a. Study the diagram and answer the following questions
i. What is the name and disease caused by this organism? (2)
The organism shown in the diagram is Trypanosoma brucei, a flagellated protozoan parasite
belonging to the group Euglenozoa. In humans, the pathogenic subspecies Trypanosoma
brucei gambiense and Trypanosoma brucei rhodesiense cause human African
trypanosomiasis, commonly known as sleeping sickness (CDC, 2025; WHO, 2023). The
parasite is transmitted through the bite of an infected tsetse fly.
ii. What animal acts as a reservoir source for this highly pathogenic organism? (1)
For T. b. rhodesiense, domestic cattle are an important animal reservoir, although several
wild animals can also maintain the parasite. In southern and eastern Africa, wild animals
such as antelope and other game animals may contribute to transmission (CDC, 2024; WHO,
2023).
iii. Where in the human body will you locate this parasite? (1)
The parasite is found mainly in the blood and lymphatic system, and during the later stage of
infection it can enter the cerebrospinal fluid and central nervous system. This invasion of the
nervous system is responsible for many of the neurological symptoms associated with
sleeping sickness (CDC, 2019).
iv. Explain the term “vector”. (2)
A vector is a living organism, usually an arthropod, that transmits an infectious pathogen
from one host to another. In African trypanosomiasis, the tsetse fly (Glossina species) acts as
DUE DATE:15 SEPTEMBER
QUESTION 1
a. Study the diagram and answer the following questions
i. What is the name and disease caused by this organism? (2)
The organism shown in the diagram is Trypanosoma brucei, a flagellated protozoan parasite
belonging to the group Euglenozoa. In humans, the pathogenic subspecies Trypanosoma
brucei gambiense and Trypanosoma brucei rhodesiense cause human African
trypanosomiasis, commonly known as sleeping sickness (CDC, 2025; WHO, 2023). The
parasite is transmitted through the bite of an infected tsetse fly.
ii. What animal acts as a reservoir source for this highly pathogenic organism? (1)
For T. b. rhodesiense, domestic cattle are an important animal reservoir, although several
wild animals can also maintain the parasite. In southern and eastern Africa, wild animals
such as antelope and other game animals may contribute to transmission (CDC, 2024; WHO,
2023).
iii. Where in the human body will you locate this parasite? (1)
The parasite is found mainly in the blood and lymphatic system, and during the later stage of
infection it can enter the cerebrospinal fluid and central nervous system. This invasion of the
nervous system is responsible for many of the neurological symptoms associated with
sleeping sickness (CDC, 2019).
iv. Explain the term “vector”. (2)
A vector is a living organism, usually an arthropod, that transmits an infectious pathogen
from one host to another. In African trypanosomiasis, the tsetse fly (Glossina species) acts as
